If you want the information to be read-only in word or any other MS Office software, there is a facility which makes this thing happen.

The trick lies in the tools menu. Go to Tools > Protect Document. There will be a menu asking of the kind of protection. If you give it as “Track Changes” then that will mark the changes in red. “Comment” will make the document read-only and wont allow any kind of changes after that.

The same option gets converted to “Unprotect” after protection is imposed. But this intern asks the same password.

Try your hands on the following document, and you will find another security trick in there. 🙂